Optical, Spin, and Vibronic Properties of the Silicon Vacancy Defects in Silicon Carbide: Robust Spin-Photon Interfaces

Over the past two decades, remarkable advances in material fabrication, optical control and spin read-out techniques have led to many successful demonstrations of quantum technologies based on defect spins in solids. Most recently, the silicon mono-vacancy defects in SiC have been identified as a promising candidate for spin-photon interfaces and quantum sensing applications. Recent optical studies of these defects have shown sharp zero-phonon-lines, high-fidelity spin read out, and long coherence times in millisecond time scales. As a next step in the development of realistic interfaces, we examine mechanisms such as vibronic coupling and Stark effect that are key to achieving spectrally narrow transitions and weak spectral diffusion. Our calculations reveal strong Jahn-Teller and pseudo Jahn-Teller effects in the V₁, V₁’, and V₂ excited states that can alter the optical emission properties of these defects significantly. We also examine the electric field response of these excited states and develop a model for the photo-induced charge conversion. Our results are in good agreement with recent high-resolution optical spectroscopy of these defects and pave the way towards robust spin-photon interfaces.